Games and social network structure

We examine repeated games played among members of a society who are connected in a social network. Players can observe each others' play, but can only directly affect the payoffs of their social neighbors. We characterize the social network patterns that sustain repeated cooperative equilibrium behavior and are robust in various ways. High levels of cooperation can only be sustained as robust equilibria in specific sorts of social networks, and so analyzing repeated games can have strong implications for how social network structure affects its members' behaviors and welfare.